The European Union has launched in 2005 its Long-Term Advanced Propulsion Concepts and Technologies project (LAPCAT). Several companies worked on this €7 million EU-funded project. For example, Popular Science reports that Reaction Engines Limited has designed an hydrogen-powered hypersonic airliner simply dubbed A2. This plane would fly at Mach 5 (3,400 mph or 5,500 km/h) on very long distances, such as non-stop flights from Europe to Australia in less than 5 hours. And because it would be hydrogen-powered, it would not release any greenhouse gases over our heads. The A2 plane has been designed to carry about 300 passengers who would pay a price equivalent to current business class tickets. The question is: will this plane ever take off? But read more...
You can see above the A2 Mach 5 plane during a potential takeoff (Credit: Reaction Engines Limited). Here is a link to a larger version of this illustration.
So this plane will be fast. But before it, the Concorde also was fast. It has been a technological success but a business failure. How will it be possible to be successful on both sides. Here is the answer from Popular Science. "Engineers created the A2 with the failures of its doomed supersonic predecessor, the Concorde, very much in mind. Reaction Engines's technical director, Richard Varvill, and his colleagues believe that the Concorde was phased out because of a couple major limitations. First, it couldn't fly far enough. 'The range was inadequate to do trans-Pacific routes, which is where a lot of the potential market is thought to be for a supersonic transport,' Varvill explains. Second, the Concorde's engines were efficient only at its Mach-2 cruising speed, which meant that when it was poking along overland at Mach 0.9 to avoid producing sonic booms, it got horrible gas mileage. 'The [A2] engine has two modes because we're very conscious of the Concorde experience,' he says."
According to the designers, this future airplane would be efficient in both modes because of its four Scimitar engines. "In the A2's first mode, its four Scimitar engines send incoming air through bypass ducts to turbines. These turbines produce thrust much like today's conventional jet engines—by using the turbine to compress incoming air and then mixing it with fuel to achieve combustion—and that's enough to get the jet in the air and up to Mach 2.5. Once it reaches Mach 2.5, the A2 switches into its second mode and does the job it was built for. Incoming air is rerouted directly to the engine's core. Now that the plane is traveling at supersonic speed, the air gets rammed through the engine with enough pressure to sustain combustion at speeds of up to Mach 5." Here is a link to a page giving more details and illustrations about the Scimitar Engine.
This plane should also be nice with our environment. [As] "it's hydrogen-powered, so it produces only water vapor and a little bit of nitrous oxide as exhaust. And although a hypersonic jet loaded with liquid hydrogen might sound dangerous, hydrogen fuel is actually no more explosive than normal jet fuel."
And don't think it will be a small plane. You can see above how big the A2 Mach 5 plane will be if you compare it to today's biggest commercial plane, the Airbus A380 (Credit: Reaction Engines Limited). Here is a link to a larger version of this illustration. You can see other pictures of the A2 Mach 5 plane by visiting this gallery provided by Reaction Engines.
And will it be expensive to travel on this plane? On this page, Reaction Engines gives the following details about a trip between Brussels and Sydney. "Analysis of the Development, Production and Operating costs suggests that the average ticket price would be comparable to an existing Business class ticket. Therefore in principle the A2 vehicle could capture all of the current business and first class traffic due to the greatly reduced journey time of 4.6 hours compared to the current 22 hours."
I'd love to fly to Australia in less than 5 hours, but I'm doubtful that such a plane will be built anytime soon. Please drop me a note if you have more information about this project.
Sources: Michael Belfiore, Popular Science Online, January 23, 2008; and various websites
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